package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

/**
 * @author walls1717
 * @since 2022/8/2
 **/
public class SimpleRedisLock implements ILock {

    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }
    private final String name;
    private final StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    @Override
    public boolean tryRedisLock(long timeoutSec) {
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        Boolean result = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name, threadId + "", timeoutSec,
            TimeUnit.SECONDS);
        // 防止自动拆箱引起空指针异常
        return Boolean.TRUE.equals(result);
    }

    @Override
    public void unlock() {
        // 调用lua脚本
        stringRedisTemplate.execute(UNLOCK_SCRIPT, Collections.singletonList(KEY_PREFIX + name),
            ID_PREFIX + Thread.currentThread().getId());
    }

    /*@Override
    public void unlock() {
        // 获取线程标识
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        // 获取Redis中的线程标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
        // 判断Redis中的线程标识是否与当前线程一致
        if (threadId.equals(id)) {
            // 一致释放锁
            stringRedisTemplate.delete(KEY_PREFIX + name);
        }
    }*/
}
